JPS639626B2 - - Google Patents

Description

[Detailed Description of the Invention] Conventional direction finders generally use mechanical goniometers, but because such direction finders have low responsiveness, they cannot detect the direction of arrival of pulsed radio waves such as static electricity. cannot be measured. Therefore, such measurements require a Watson-Watt type direction finder, but if an omnidirectional antenna and, for example, two sets of directional antennas are used, three reception units with equal phase characteristics and amplification can be used. Since it requires a machine, the configuration is complicated and the adjustment operation is extremely complicated. The present invention provides a direction finder that does not have such drawbacks and can stably obtain high-speed indicating characteristics.

Fig. 1 is a configuration diagram of an embodiment of the present invention, in which the outputs of directional loop antennas An and Aw are applied to switch circuits S1 and S2, and the output of an omnidirectional vertical antenna As is applied to a phase shifter P at 90 degrees. By shifting the phase, it is made to have the same phase as the output of the loop antenna and is added to the switch circuit S3. In addition, the output of the clock pulse generator O as shown in Fig. 2a is input to the frequency divider D.
The frequency is divided by , to form three-phase control signals such as b, c, and d, and these signals are used to close each of the above-mentioned switch circuits. Therefore, the switch circuit S1,
The outputs of the antennas An, Aw, and As are sequentially switched and applied to one receiver R by a first switching circuit including S2, S3, the frequency divider, and the like. This receiver R delivers a suitable intermediate frequency output and applies this together with the output of the local oscillator L to a frequency converter M. Furthermore, the output of the converter M and the output signal P obtained from an appropriate stage of the frequency divider D are added to the phase discriminator K, and the oscillator L is controlled by the output, thereby forming a phase lock loop. The output of the converter M is synchronized with the output signals b, c, and d of the frequency divider D, and the zero phase point in the output is the signal b,
It coincides with the rise and extinction points of c and d. The output of this converter M is applied to switch circuits S4, S5, and S6, and each of the switch circuits is closed by the three-phase control signals b, c, and d. Therefore, switch circuits S4, S5, S6 and frequency divider D
A second switching circuit, comprising a second switching circuit, operates synchronously with the first switching circuit to distribute the output of the frequency converter.

Figure 2 e, f, and g show the outputs distributed as described above, and their amplitudes are
Corresponding to the outputs of An, Aw, and As, the phases are the same or opposite to each other. These outputs e and f are digital analog signal delay circuits B1 and B2 configured with charge transfer elements (BBD or CCD).
In addition, by driving the element with the output pulses of the clock pulse generator O, the signals b, c,
When the time width of d is T, output e is given a delay of 2T, and output f is given a delay of T. Note that the delay time of the delay circuits B1 and B2 is given by N/2, where the number of charge transfer stages is N and the frequency of the drive pulse is N/2, so this value is the above 2T or T. The number of stages is selected so that As mentioned above, since the outputs e and f are given delays of 2T and T by the delay circuits B1 and B2, respectively, they are sent out simultaneously with the output of the switch circuit S6. Therefore, when the outputs of the delay circuits and the switch circuits are respectively applied to amplifiers A1, A2 and saturation amplifier A3, we get
Outputs such as those shown in FIG. 2 h, i, and j are sent out from these amplifiers. When the outputs h and i are used as vertical and horizontal deflection inputs of the cathode ray tube B, and the output j is used to modulate the brightness of the cathode ray tube, a radial bright line x appears on the screen.

That is, the period of the signal P applied from the frequency divider D to the phase discriminator K of the phase lock loop is controlled by the control signal b,
When the time width T of c and d is set to an integer fraction, the local oscillator L is controlled so that the output of the frequency converter M is synchronized with the signal p regardless of the phase of the intermediate frequency output sent from the receiver R. done, switch circuit S
4, S5, and S6 output wave numbers e, f, and g given by integers, respectively. and output e,
Since f is delayed by a time 2T or T, which is an integral multiple of its period, the outputs h, i, and j of amplifiers A1, A2, and A3 also maintain the same or opposite phase states. Also, the amplitudes of outputs h and i are determined by the directional antenna.
Corresponding to the outputs of An and Aw, these become the vertical and horizontal inputs of the cathode ray tube B, and brightness modulation is performed by the rectangular wave output j. Therefore, the emission line x has a direction corresponding to the directivity of the antennas An and Aw on the screen of the cathode ray tube B, and is a composite of vectors n and w whose size corresponds to the amplitude of the outputs h and i, Furthermore, bright lines corresponding to positive or negative half cycles of outputs h and i are eliminated by brightness modulation. Therefore, the direction of arrival of the radio wave can be determined from the direction of the bright line x.

As described above with respect to the embodiments, the direction finder of the present invention can perform direction measurement using the Watson-Watt method using one receiver. Therefore, it is possible to accurately and stably measure the direction of arrival of pulsed radio waves without requiring difficult adjustments to match the amplification and phase characteristics of multiple receivers, which is required when using multiple receivers. It is.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of an embodiment of the present invention, Figure 2 is a diagram showing the configuration of an embodiment of the present invention.
The figure is a waveform diagram for explaining the operation of the apparatus of FIG. 1. In the figure, An and Aw are directional antennas, As is an omnidirectional antenna, P is a phase shifter,
S1, S2, S3 and S4, S5, S6 are switch circuits, R is a receiver, M is a frequency converter, L is a local oscillator, K is a phase discriminator, D is a frequency divider, O is a clock pulse generator, B1 and B2 are signal delay circuits, A1, A2, and A3 are amplifiers, and B is a cathode ray tube.

Claims (1)

[Claims] 1 An antenna system consisting of an omnidirectional antenna and a plurality of directional antennas, one receiver, a first switching circuit that sequentially switches the output of each antenna in the antenna system and applies it to the receiver, and a phase lock loop. a frequency converter inserted therein to which the output of the receiver is applied; a second switching circuit operating synchronously with the first switching circuit to distribute the output of the frequency converter; a plurality of delay circuits configured with charge transfer elements so as to add the respective outputs distributed by the two switching circuits and send them out simultaneously; 1. A direction finder comprising a cathode ray tube in which the output obtained by each of the omnidirectional antennas is used as a deflection input, and the output obtained by the omnidirectional antenna is used as a brightness modulation input.